What'd I'd love to see is something that is a WYSIWYG interface for editing Markdown. Markdown is fantastic and awesome because it limits what people can do, but expecting clients to learn it is a pain in the arse.
Looks great, but by default it subjects the user to the markdown gotcha of wanting to italicize text_with_underscores_in_it. EpicEditor, by contrast, has italicizing underscores_inside_words turned off.
